A number of medical and cosmetic applications and treatments involve controlled injection of substances into the body.
A medical syringe is a simple piston pump consisting of a plunger that fits tightly in a cylindrical barrel. The plunger can be pulled and pushed along inside the barrel, allowing the syringe to take in and expel a fluid through an orifice at the distal open end of the barrel. The distal end of the syringe is typically fitted with a hypodermic needle to introduce the barrel's fluid into a patient. Surprisingly, other than the materials used to make a syringe, the typical disposable syringes are much the same as the very earliest syringe designs.
Unfortunately, classic syringe/needle systems are far from optimal for the administration of today's injectable aesthetic compositions. Hydrogel-based dermal fillers can be quite difficult to inject using the conventional syringe/needle system or conventional injection techniques. Many dermal fillers are by their nature highly viscous, thus requiring relatively high extrusion forces, especially when injected through preferred fine gauge needles. Moreover, these materials are typically injected into the face to correct wrinkles, including fine wrinkles as well as other minor defects in skin, and therefore, must be sometimes injected in trace amounts, and always with very high precision. Interestingly, these dermal fillers are commonly introduced into skin using quite standard needle and syringe combinations.
Using a traditional syringe and needle combination, physicians can be required to apply the needle at a shallow angle relative to the skin of a patient. It can be difficult to precisely control the needle to a predetermined location during an injection. Accordingly, a need exists for further development of injection devices.